The present invention relates to a conductive plate, and more particularly relates to improvement in the state of dispersion in a conductive plate made of dispersion strengthened copper alloy.
A conductive plate of the above-described composition per se has been well known in the field of art. Such a conductive plate is used, for example, for a lead frame which requires high strength and high thermal conductivity.
In the construction of the conventional conductive plate of this sort, Al.sub.2 O.sub.3 fine particles are almost uniformly dispersed in the thickness direction of the conductive plate. Further, Al.sub.2 O.sub.3 is oriented in the form of fine threads in the direction of rolling or extrusion employed at production.
When such a conductive plate is used for production of lead frames, bending is applied in most cases to the conductive plate. Since Al.sub.2 O.sub.3 is oriented in the form of fine threads, the conductive plate is vulnerable to bending along lines parallel to the direction of orientation. Such low resistance to bending allows easy generation of cracks in the surface section at bending and cracks are liable to cause total breakage of the conductive plate. In conclusion, the conventional conductive plate of this sort is quite unsuited for bending at production of various articles therefrom.